A self-assembled pattern forming method using a block copolymer is expected as a method of producing a recording device such as a bit patterned medium. The bit patterned medium has dots of magnetic material for each predetermined number of bits (for example, one bit) and is promising as a future recording medium of a hard disk drive. A regular array of dots in a large area with less array defects can be formed in a high density by making the block copolymer self-assemble while starting from dummy guide dots.
Here, the dummy guide dot needs to have a small size at the same level as that of the pattern to be formed by the self-assembly. The dummy guide dot can be produced by photolithography or electron-beam lithography. In this case, however, the advantage of miniaturization by the self-assembly cannot be sufficiently exhibited because of a problem of the resolution of a lithography device.
To solve this problem, a technique of reducing the size of the pattern produced by the lithography to obtain a fine pattern has been developed. The pattern formed by the lithography can be reduced in size by using a self-assembling material. By using this method for dummy guide dot array formation, the dummy guide dot exceeding the limit of the lithography can be formed.
Incidentally, in the recording device such as the bit patterned medium, it is necessary to form a pattern with a large size (for example, a positioning pattern (in the case of the bit patterned medium), a wiring pattern (in the case of the electronic device)) in addition to a pattern of fine dots.
However, it is not always easy to produce on the same substrate both of the fine dot pattern and the pattern with a size larger than that of the dot by the method using self-assembly.